Abstract

Westralunio carteri Iredale, 1934 is the only freshwater mussel in south-western Australia. Like other freshwater species, it is likely to be responsible for providing valuable ecosystem services including water filtration, sediment oxygenation, structure to stream banks and sediment support, food for other animals including waterbirds, water rats, marron, and shells provide refuge for other small aquatic animals. At one time, the mussel was an important food source for the Noongar people.

Since land clearing began in the late 1800s, dryland salinity has caused the species to disappear from much of its former range. It is intolerant of salinities above 3.0 ppt. A recent survey of the lower Canning River (downstream from a point above Royal Street Bridge) and lower Yule Brook (between the confluence with Canning River and just downstream from Kenwick Link) revealed that the species had undergone 100% mortality in these areas, which probably resulted from the upstream movement of a salt wedge in these systems, although water loss and drought-like conditions in 2009 and 2010 in lower Yule Brook may have also caused deaths from dehydration.

To determine whether living W. carteri populations remain in Yule Brook above Kenwick Link, and to determine their population structure, an ecological survey was conducted during March, 2012.